The most urgent thing to do is fill the user gap. To do it we'll focus our work/time in the user applications like kbluetooth and a possible kioslave.
Once the user stuff is in a good shape, we'll start to "move" all the development we made for the user applications to solid/bluetooth and solid/bluez, so everybody will benefit of it.

Before 0.4 version, kbluetooth was thought as a framework and is because of it that kbluetooth is divided in 3 programs, kbluetooth, kbluetooth-devicemanger and kbluetooth-inputwizard. Everything will be merged in kbluetooth.

Then, all classes will be refactored/revised, and the new features which are not in solid will be totally rewritten from scratch (if needed), so we can move it easily to solid in the future (send, receive files for example).

The current bluetooth code is messed because the last development was stopped in the middle of a big refactoring. Despite it, everything is working quite well.
While we're working on user stuff, we'll maintain solid as it is, but once finish it, the plan is design a good API to introduce a real bluetooth integration in kde.